Casey Kasem, the legendary radio DJ and TV voiceover artist, is in advanced stages of Parkinson's and his three grown children from his first marriage want to see him before it's too late. But they say his second wife
Jean Kasem, a
"Cheers" actress whom Kasem married in 1980,
is keeping him from them and they have now taken legal action.

People reports the papers were filed in Los Angeles Superior Court this week, with daughter
Julie, 38, (above, right) asking for a conservatorship over Kasem's healthcare. The kids have repeatedly said their quest to see their father
has nothing to do with money.

Daughter
Kerri, 40, (above, left) tells
US Weekly, "It's been really difficult, but I am hoping [Jean] comes out and says, you know, 'I'm sorry. Of course you can see your dad.' But we've heard nothing from her. Nothing. So our next step is legal action."

Starting back on Oct. 1, the three children plus Kasem's brother Mouner and more than a dozen of Kasem's friends started staging a protest outside his Beverly Hills mansion in the hopes of gaining access to Kasem, but Jean reportedly called the cops on them.

The children say they have never had a good relationship with Jean, but have always been close with their father.

"Every single day before my dad got too sick to talk on the phone, I talked to my dad. He talked to every single one of us once a day -- we were that close ... So to just rip him from us and say, 'Sorry! He's just going to die with me, and you're not going to know about it, and we're not going to tell you anything, and you're not going to have a number to the house, to his caretakers, to his doctors...' It is beyond me," says Kerri.

"We don't have a relationship with [Jean]. I mean, literally, I haven't been to that house in more than a decade. I have seen Jean twice in 15 years ... And it's like, nobody's fighting; she just has never wanted a relationship with us."

Jean Kasem has continually remained mum regarding the entire situation.